**3. Grapes as functional foods**

Foods that promote human health and well-being are core segments of fastmoving consumer goods, with a growing awareness of the food-health relationship among consumers around the world. Due to the richness and variety of bioactive substances contained in grapes and their positive effects on human health, they are an important raw material for various applications.

Grapes from varieties cultivated in Romania contain significant concentrations of phenolic compounds with a strong antioxidant activity [36]. The *Argensis* variety offers the properties of low sugar content and high acidity, and is very appreciated in the diet of diabetics [37].

Some other studies of recent years [38–44] have aimed at studying bioactive compounds that are present in food, and have properties that may contribute to protection against chronic diseases.

A significant interest for the potential health effects of some phytochemicals such as flavonoids and other polyphenolic compounds was noticed in the last period. Thus, potential health benefits of compounds such as isoflavones and/or resveratrol etc. have been evaluated against cardiovascular diseases [45, 46], cancer [47–49], osteoporosis [50], and cognitive decline [51]. The potential mechanisms and food safety issues have been discussed in relation to their potential health contribution.

The presence of phenolic compounds in the diet has been a negative feature for a long time, if they reduce the availability of nutrients, leading to a low nutritional value of food. Since the 'French paradox' was identified, and highlighting that a moderate consumption of red wine (rich in polyphenols) contributes to lowering the rate of cardiovascular morbidity among the French population, special attention was paid to the study of phenolic compounds as food ingredients [52]. Currently, numerous studies indicate that the presence of phenolic compounds in food is important in terms of their antioxidant stability and antimicrobial protection [52–54].

*Romanian Organic and Conventional Red Grapes Vineyards as Potential Sources… DOI: http://dx.doi.org/10.5772/intechopen.98972*

Innovation in the field of functional foods must constantly guarantee the safety of products [55]; contributes to the improvement of the nutrition - health relationship, by substantiating it on a scientific basis; contributes to the conservation of biodiversity and the sustainable development of the food sector [56–58].

The sanogenic effects of polyphenols depend on the amount consumed and their bioavailability [59, 60]. The bioavailability of polyphenols is the subject of various research, in particular on intestinal absorption and influencing factors (chemical structure – e.g., glycosylation, esterification and polymerization, food matrix, etc.). According to the World Health Organization report published in 2003, over 50% of the population of Europe, North America and other industrialized regions have used complementary natural medicines at least once [61]. Regarding to the sanogenic effect of polyphenols in grapes, even if there is a series of research in this field, there is still a wide range of untapped information [62, 63]. On the other hand, taking into account the multitude of foods, with synthetic chemical compounds that become toxic to the body, especially when certain substances reach the systemic circulation, it is desired to find new natural and non-invasive solutions such as "health-protective foods", beneficial for various diseases often caused by pollution, an accelerated pace of life, uncontrolled eating [64, 65].

Starting from the practical uses of grapes, as food, their bioactive compounds and derived products are associated with the prevention of many pathophysiological processes, including cardiovascular and neurodegenerative diseases, tumor diseases, diabetes, and other illnesses. A correct and complete understanding of phytochemical compositions and antimicrobial activities of different anatomical parts of grapes from *Vitis vinifera L.,* as well as differences resulted from the variety and/or the culture management system, may lead to developing new applications, much more specific, from a wide spectrum already known. Thus, recent studies [19, 40, 66–69] have shown a direct relationship between the therapeutic benefit, chemo-preventive effects (anticancer) and the red grapes consumption, in various forms. The role of the bioactive compounds (*e.g.,* proanthocyanidins, anthocyanins and other flavonoids, hydroxycinnamates, and stilbenes such as resveratrol) has been investigated, and antioxidant, antimicrobial, antitumor effects have been found, as well as anti-inflammatory properties, and inhibiting lipid peroxidation. Thus, the use of expression 'health-protective biomolecules' in relation with these compounds looks appropriate.

A lot of attention was paid in the last period of time, both in research and development in the food industry, to functional foods and beverages, formulated with natural ingredients, with certain and scientific substantiated target physiological functions. Some of the functional beverages existing on the market include grapes and their derived products as source of biological active compounds. Not in the last, dairy products and meat products are ideal matrices [62].

Grape products, such as grape juice and grape skin extract, can be incorporated into yogurt, resulting in an increase in the content of phenolic compounds and antioxidant capacity. The degree of acceptability by consumers, from sensorial point of view, was high, aspect important in terms of product marketability [56, 58, 62].

Phenolic compounds are widely distributed in grapes [30, 54, 63]. The phenolic composition of a single grape variety depends on the anatomical part (whole grape pulp, skin or seeds). Grape extractable phenolic compounds represent 10% or less in pulp, 60–70% in seeds and 28–35% in skin. The phenolic content of the seeds can range between 5% and 8% by weight. Grape seed extracts are very good source of proanthocyanidins (usually oligomers and polymers of polyhydroxy-flavan-3-oils, *i.e.* catechin and epicatechin), many in the form of gallate or glycosides [30, 70].

About 75% of the world's grape production is destined for the wine industry, so that grape pomace is an abundant by-product of the wine industry. In total, residual skin, seeds and stalks forming pomace represent approximately 25% of the total weight of the grapes used in the winemaking process [50]. In fact, grape pomace consists of two fractions: pomace without seeds (residual pulp, skin and stalks) and seeds [50]. Both fractions are rich in bioactive compounds, such as phenolic compounds [37].

The most abundant phenolic compound in pomace is represented by anthocyanins concentrated in the skin, respectively flavonols present especially in seeds, ranging from 56 to 65% of the total. Recent studies have shown the potential for recovery of phenols and antioxidant fibers from skin, respectively of seed oil from pomace [64, 71]. Considering that phenolic compounds are the most important secondary metabolites with antioxidant properties in grapes, the total content of phenolic compounds in grape pomace extracts is usually well correlated with their antioxidant activity [30]. Extracts obtained from pomace can be used in food, pharmaceuticals, cosmetics and other products in the form of liquid extracts, concentrates or powders [64]. Grape pomace extracts have been used as food protection factors due to their antioxidant capacity, prevention of lipid oxidation in fish products, and antimicrobial activity against various bacterial strains, such as *Staphylococcus aureus*, *Bacillus cereus*, *Campylobacter coli*, *Escherichia coli* O157: H7, *Salmonella infantis*, *Listeria monocytogenes* ATCC 7644. Bactericidal effects against mesophilic aerobic bacteria, lactic acid bacteria and enterobacteriaceae was showed by the seedless grape pomace products [33].

A high antioxidant capacity of the grape pomace flour sustains the delayed lipid oxidation, this property being by high interest in the context of concerns regarding the use of natural antioxidants in foods, in order to find out an alternative to the widely used synthetic ones.

Grape pomace extracts have nowadays a wide range of applications, from fortified beverages and yoghurts and use as ingredient in osmotic solution to obtain dehydrated fruits with high phenolic compounds to cosmetic applications. Not in the last, the extracts obtained from grape pomace were successfully incorporated into edible chitosan films, both hydrophobic and hydrophilic, providing antioxidant properties and prolonging life of the food products [44, 58, 64, 65, 71]. Grape seed extracts, rich in polyphenols, have been used to reduce the formation of acrylamide during the Maillard reaction [53].

Cosmetics with grape polyphenols are currently marketed, such as day or night cream and face serum from Pure Super Grape® (Marks and Spencer - UK), mattifying, anti-wrinkle and anti-wrinkle protection fluid from Caudalíe® (France). There are few brands in the field of food supplements that claim to use polyphenols, mainly resveratrol, from grapes. For example: 100 Natural®, Nature's Way®, Maximum Strength®, GrapeSeedRich®. These products confirm the commercial potential of bioactive compounds extracted from grapes or grape by-products [65, 72]. Some studies showed the differences in phenolic compounds concentrations in grapes anatomical parts. Thus, phenolic compounds concentration in seeds (70%) is higher than in skin (20%) and in pulp (10%) [73].

Recent research has evaluated the use of pomace flour from grapes and seeds, respectively, in various products such as popcorn, cereal bars, biscuits and cookies, extruded snacks and muffins, resulting in high-fiber products with antioxidant potential and consumer acceptability.

Pinot Noir grape fiber can be used as an alternative source of antioxidants and dietary fiber when added to yogurt and salad dressing, not only to increase the content of fiber and phenols, but also to delay the oxidation of lipids during storage, expanding shelf life of these products.

The addition of grape pomace fiber to unconventional products, such as cod and seafood, has led to a minimization of changes in flavor, color, texture and oxidation

*Romanian Organic and Conventional Red Grapes Vineyards as Potential Sources… DOI: http://dx.doi.org/10.5772/intechopen.98972*

of lipids during freezing. The antioxidant dietary fiber in grapes added to chicken breast burgers and fish muscles has led to improved oxidative stability and free radical scavenging activity [62, 73].

According to some authors, a percentage between 2 and 5% of the grapes weight is represented by grape seeds that constitute approximately 38–52% of the solid waste generated by the wine industry. In general, grape seeds contain about 40% fiber, 10–20% lipids, 10% protein, phenolic complexes, as well as sugars and minerals. About 80% of the sugar-free dry matter of the grape seeds consists of indigestible fractions, mainly cellulose and pectins [30, 73].

Grape seeds are highly appreciated for the nutritional properties of their oil, known as rich source of unsaturated fatty acids (oleic and linoleic), and phenolic compounds [73]. Grapes seed oil is widely marketed in some countries, and is used for years in numerous applications, especially in cosmetics formulations [41, 62, 71]. However, recently reported data have confirmed its promising bioactive properties and new specific uses for obtaining organic products.

Grape seeds contain 8–15% (w/w) oil with a high content of unsaturated fatty acids (oleic acid and linoleic acid), which represent more than 89% of the total essential fatty acids. Linoleic acid is an essential fatty acid receiving a lot of attention, together with the conjugated linoleic acid, due to their biological effects. Thus, recent studies have shown the beneficial effects of the grape seed oil, such as hepatoprotective, neuroprotective action and in reducing the level of cholesterol in the liver [42, 46–48].

In the food industry, grape seed oil can promote lower production costs, as it is more competitive compared to other types of oil in economic terms, and may be a new food source for human consumption. In addition, grape seed oil has a high burning point, which is why it can be considered as a potential biodiesel [11].

Food industry is constantly searching for new strategies that may lead to inhibition of the spoilage microorganisms growth. Recent studies focused on new natural compounds with antimicrobial activity capable to replace classical chemical preservatives. Several products obtained from grape pomace, in particular from grape seeds, have been proposed to act as food spoilage control additives.

The growth of mesophilic aerobic bacteria, lactic acid bacteria, *Pseudomonas* and psychotrophic populations in pork pate was delayed by the incorporation of grape seed extracts, which showed a higher antimicrobial action compared to other natural extracts (obtained from tea, seaweed and chestnuts).

Grape seed extracts showed bactericidal effects against *Escherichia coli* and *Salmonella typhimurium* and delayed the growth of *Listeria monocytogenes* and *Aeromonas hydrophila*. Incorporated in films, grape seed extracts showed a slight activity against *B. thermosphacta*. Grape seed extracts were also effective in cheese inoculated with *L. monocytogenes*, *Staphylococcus aureus* and *Salmonella enterica*. The concentrations required to observe the antimicrobial effect were higher than in the *in vitro* tests, which suggested a decrease in the antimicrobial effect when the extracts were added to food. This inferior effect can be explained through a reduced solubility of extracts in certain foods and the interaction of polyphenols with other food components too. Grape seed extracts have a higher activity of inhibiting microorganisms, compared to the extracts obtained from the skin of the same grape varieties.

The antimicrobial effect of the grape pomace products is usually attributed to different phenolic compounds. Several studies have shown the predominant role of the phenolic acids (mainly gallic acid, followed by p-hydroxybenzoic and vanillic acids) compared to flavonoids. In this respect, gallic acid has been shown to be the strongest antimicrobial agent in grape seed extracts [53, 54]. Although the effect of inhibition of spoilage and pathogenic microorganisms by grape extracts has been

widely studied, there is still some research that highlights the ability of products obtained from pomace to promote activity or protect probiotic microorganisms against various external factors.

The effect of phenolic compounds on the growth of lactic acid bacteria may have a significant variation, depending on the chemical structure and concentration of each phenolic compound, the species of microorganisms, their growth in the environment and the growth phase. Some authors found that pomace and grape seed extracts have promoted the growth of *Lactobacillus acidophilus* [62].

Procyanidin extract from grape seeds has shown anti-obesity properties in animal and human studies. Recent studies suggest that procyanidin extract from grape seeds has a protective effect on intestinal permeability, but the mechanism is still unknown. The extract has been reported to have anti-inflammatory and antioxidant properties and the ability to modulate the intestinal microbiota. Based on these properties, it was supposed that the mechanism of intestinal barrier function mediated by procyanidin extract from grape seeds is associated with reducing the inflammation and changes within the intestinal microbiota [42, 74].

Some *in vivo* studies have shown that bioactive compounds from grapes skin improve the glutathione metabolism and reduce the apoptosis. The grape skin powder promoted the regeneration of glutathione and the reactivation of glutathione-dependent antioxidant enzymes, helping to maintain redox homeostasis and protect the intestinal mucosa against apoptosis in a model experiment of ulcerative colitis. All the fractions obtained from the skin of the grapes were equally useful for restoring homeostasis in the colon. It has been suggested that dietary fiber and grape-associated polyphenols are much more effective compared to extractable polyphenols to protect the intestinal mucosa from ulcerative lesions [45, 51, 74].

Recent research work using a system of ultra-high performance liquid chromatography coupled with mass spectrometry (UHPLC–MS/MS) on Tannat grape skin extracts showed that the main polyphenols constituents are flavonoids, phenolic acids and phenols. Also, the study demonstrated the bioavailability of these compounds *in vitro*, with the potential to modulate key biochemical activities involved in the pathogenesis of diabetes and the control of hyperglycaemia caused by this disease [37].
